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TURNING UP the HEAT

Bob Kostash fights fire with fire in this discussion on Canada's second-rate cable jacket fire ratings.


March 1, 2000  


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Canada has an admirable record of leadership in issues affecting the health, safety and well being of its citizens. New prescription drugs undergo extensive testing in Canada before being allowed onto the market — often years after they are available in other parts of the world. And automotive emission and safety standards in Canada are amongst the toughest on the planet.

Yet, in our own industry there exists a glaring exception to Canada’s general rule of safety and equality: Canadian regulations for the burn-resistance of cable jacketing materials are inconsistent across the country, and default to a lesser standard than in the U.S.

Imagine if automobiles in Ontario were required to have air bags, but those in Manitoba did not require the safety devices. Imagine a Pee Wee hockey tournament at which one team was required to wear helmets and facemasks, and the other team was allowed to go helmet- and mask-free. To Canadians, both instances are illogical.

A TALE OF TWO BUILDINGS

Here is the cabling industry parallel. Picture two commercial office towers, each housing a high tech call centre tenant. Each call centre has a LAN built with Category 5e quad drops to every work area. The cubicles are small (6 by 8 feet), resulting in very high cable densities in the ceiling. As is common building practice today, the space between the suspended ceiling tiles and the concrete slab above is used as a plenum for handling return air flow for the heating and air conditioning system.

Let’s say a fire breaks out in each of the two towers on the same day. The fires begin at floor level underneath an area of high cable concentration. In the first building, the cable catches fire. Because the cable is located above the sprinkler system, the fire continues from room to room along the cable path. As the cable burns, it drops flaming balls of molten plastic, which start more fires where they land. It also emits large volumes of smoke. The heating system continues to operate, drawing the smoke through the plenum and re-circulating it throughout the building. The fire and sprinkler system damage every workstation and office on the floor. The call centre’s main telecommunications closet and server-room are destroyed. People throughout the building are treated for smoke inhalation.

In the second building, the fire also ignites the LAN cables. The flames begin to spread along the cable, but as they move further away from the source of the fire, the cable self-extinguishes and minimal smoke is produced. The sprinkler system puts out the fire in the room below. The economic impact on the call centre and the building’s other tenants is significantly less than in the first fire.

The National Building Code in Canada states that cables meeting the CSA FT-4 requirement for flame spread are approved for use in plenum spaces. However, several jurisdictions in Canada rule that this is an insufficient requirement. In Ontario and in the City of Vancouver, building codes require the much more stringent FT-6 requirement for any cable that is to be placed in an air plenum. So, fictional fire number two could occur in Ontario or Vancouver, while fire number one could have been in any other city, province or territory in Canada.

Clearly, this disparity is as absurd as the hypothetical hockey helmet and airbag examples. But this disparity is real!

CANADA VS. AMERICA

The U.S. National Building Code requires CMP (Underwriter’s Laboratories’ equivalent of CSA’s FT-6) be used in plenum spaces in all 50 states. In some municipalities in the U.S., no cable is allowed in plenum spaces outside of EMT conduit.

In other words, Canada’s standard is inferior to the American standard — except in Ontario and in the City of Vancouver. Should this be acceptable to Canadians?

Canada’s National Building Code adopted the FT-4 standard in the early 1980s, just prior to the networking revolution that has swept the modern world. The cable-based fuel load in a typical plenum ceiling at that time was a fraction of what it is today. (Remember that LANs were based on bus architecture at that time — not the star topology of today. One thin-net cable could feed 30 workstations, while 60 or more cables would be run to the same number of workstations today). This is a clear technical justification to revisit the code.

It is well past time that the National Building Code, Canadian Electrical Code, Canadian Standards Association and other provincial and municipal code authorities rectify a serious life-safety issue. Canadians can not, and should not, be treated differently in areas of safety, and they certainly should not be subjected to an inferior standard to the one in place south of the border.CS

Bob Kostash is National Sales Manager, Global Private Systems at Lucent Technologies Canada Inc. in Toronto.


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